1. Field of the Invention
The present invention is directed generally to radio frequency monitoring and, more particularly, to a system and method for radio frequency intrusion detection.
2. Description of the Related Art
The problem of radio transmission security has existed almost since the invention of the radio. In one aspect, security involves the prevention of the interception and decoding of radio transmissions. However, in another aspect of radio security, it is desirable to detect and/or prevent unauthorized radio transmissions.
For example, an organization, such as the government, may wish to prevent unauthorized radio transmissions from a secure location, such as a military base, laboratory, a prison, or the like. One technique used to prevent unauthorized radio transmissions is to design a secure room that has shielding to prevent any radio transmissions. A technology known as Telecommunications Electronics Material Protected from Emanating Spurious Transmissions (TEMPEST) utilizes materials with special shielding properties. Passive systems such as TEMPEST protection are prohibitively expensive and are not technologically feasible for a large area, such as a military base or a prison.
Another alternative approach is to construct a Faraday cage around the secure room. Radio frequency signals are applied to coils that comprise the Faraday cage and block any radio frequency transmissions emanating from within the cage. Aside from the health issues associated with such an active Emissions Security (EMSEC) technology, the cost is significant. In addition, a Faraday cage is not technologically feasible for an area larger than a single room. In particular, Faraday cage technology would not work in a large compound, such as a military base, a prison, or the like.
Therefore, it can be appreciated that there is a significant need for a system and method to detect radio frequency intrusion within a secure area. The present invention provides this, and other advantages as will be apparent from the following detailed description and accompanying figures.